Introduction: Lumbar interbody fusion via lateral access (LLIF) has received considerable attention as a less invasive alternative to traditional anterior access (ALIF). However, no studies exist prospectively evaluating the two techniques in patients undergoing circumferential fusion. This study compared short-to-midterm follow-up outcomes of subjects who received intervertebral arthrodesis via a lateral or anterior approach supplemented with posterior fixation.
Methods: This was a prospective multi-center (11 investigators) study of 103 subjects receiving single-level ALIF or LLIF with supplemental interspinous process fixation (ISPF) or pedicle screw fixation (PSF) for the treatment of degenerative disc disease +/- spondylolisthesis. The interbody approach was per investigator institutional standard-of-care (ALIF=46; LLIF=57). Subjects were randomized 2:1, ISPF to PSF, for the posterior construct. The PSF (MIS or open; unilateral or bilateral) was performed at the investigator’s discretion. Intraoperative outcomes and patient-reported outcomes at 1.5, 3, 6, 12, and 24mo. were collected and stratified by circumferential construct type. Note: Outcomes through 12mo are reported here; 24mo outcomes to be available at time of presentation. Comparative analysis was performed using a linear mixed model (p<0.05).
Results: Sex, age, and BMI were not significantly associated with any outcome. With respect to mean ODI change from baseline, the only significant difference was between LLIF+ISPF and ALIF+ISPF cohorts at 6 weeks, with LLIF subjects demonstrating a significantly greater decrease (p=0.02). No other statistically significant differences were observed between the respective cohorts for ODI change, change in SF-36 scores (mental and physical), and change in ZCQ scores (physical, symptom, and satisfaction) across all observed timepoints. Complication profiles were comparable between cohorts; no incidence of symptomatic cage migration or subsidence was observed.
Conclusions: At 1-year, patient-reported outcome scores demonstrated significant pain reduction and satisfaction with all circumferential constructs; LLIF+ISPF performed most advantageously in the early post-op period.
Patient Care: This prospective study provides patient outcomes to facilitate the decision-making process in regards to an appropriate surgical approach for circumferential fusion for degenerative lumbar spine.
Learning Objectives: By the conclusion of this session, participants should be able to discuss/identify…
1) How outcome trends compare across multiple circumferential constructs
2) Patient demographics/pathologies for which adjunctive posterior fixation may be advantageus with LLIF or ALIF
3) Potential limitations associated with circumferential LLIF and ALIF